46 research outputs found

    Nucleotide Oligomerization Domain-like receptor 4 (NLR4) Gene Expression and Interleukin 1-β (IL 1-β) Level in Urine Samples Before and After Intravesical BCG Therapy For Treatment of Bladder Cancer

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    Bladder cancer is the 7th most commonly diagnosed cancer in males worldwide and the 11th when both genders are considered. Seventy five per cent of bladder cancer cases are non-muscle invasive bladder cancer (NMIBC). Bacillus Calmette–Gu rin (BCG) immunotherapy remains the standard intravesical agent for NMIBC. The exact mechanism by which BCG prevents recurrence is unknown. The aim of this study was to evaluate NLR4 gene expression and IL-1β as possible prognostic indicators for NMIBC recurrence and BCG treatment failure, and to detect the difference in their levels among muscle invasive bladder cancer (MIBC) and NMIBC that may aid in primary differentiation between cases. This study was conducted in 30 patients who had NMIBC and 17 patients who had MIBC. Urine samples were obtained in sterile cups before operation. From NMIBC cases, four more samples were obtained as mentioned below. Evaluation of NLR4 gene expression was performed in pre-surgical sample for MIBC and in 4 samples for NMIBC: pre-surgical sample, sample collected 4 hours after the 3rd dose of BCG instillation, and samples collected during follow up (3 and 6 months post-surgically). There was statistical significant increase in NLRP4 expression levels in NMIBC (CT=0.87±1.48) compared to MIBC (CT=2.82±2.07). As far as we searched, no published results were found regarding comparative gene expression levels between NMIBC and MIBC cases. Gene expression in recurrent cases was higher in pre-surgical urine samples than in non-recurrent cases. The expression level further increased up to 21 fold than the pre-surgical level in the sample taken after injection of the 3rd dose of BCG. This level decreased distinctly to become 1-fold increase over pre-surgical level at the 3rd month follow up then to only 0.9-fold at the 6th month. In non- recurrent cases, gene expression level started pre-surgically in much lower levels than those encountered in recurrent cases. There were 11-fold increase in expression level after 3rd dose of BCG instillation and then decreased to be 5.6 folds higher in the sample taken at 3rd month follow up than in presurgical samples. Gene expression further decreased to become 4.1 fold higher in samples taken at 6 month follow up than the pre-surgical levels. IL-1β levels were estimated for NMIBC and MIBC cases in urine samples pre-surgically and during BCG therapy in case of NMIBC before and 4 hours after the 3rd dose and during 3rd month follow-up of those cases for searching its possible use of for primary differentiation between NMIBC and MIBC, and also as a prognostic factor for possible recurrence in case of NMIBC cases. The level of IL-1β was generally higher in pre-surgical samples (0.62±0.12 pg/ml) when compared to its level before the 3rd dose of BCG induction therapy (0.53±0.13 pg/ml). Its level was distinctly higher four hours after administration of the 3rd dose BCG (1.96±0.62 pg/ml) than both previous levels. Levels decreased bellow pre-surgical level at 3rd month follow up (0.57±0.099 pg/ml). The levels of IL-1β estimated in samples collected four hours after the 3rd dose BCG was higher in cases that showed recurrence later on than non-recurrent cases. The levels decreased in both cases and became higher in non-recurrent cases (0.64±0.05 pg/ml) than in cases already developed recurrence at the 3rd month diagnosed during follow-up (0.45±0.05 pg/ml). To conclude, on following NLRP4 gene expression and IL-1β levels during BCG administration among recurrent and non-recurrent cases of thirty NMIBC cases, there was a significant statistical difference in both levels for the samples collected after the third dose BCG, being higher in patients who showed subsequent recurrence at the 3rd and 6th month of follow-up. If these preliminary reported findings will be confirmed in upcoming larger cohort’s studies, it could be promising in prognosis of such cases, with the possibility of early manipulation of individualized treatment schedule, keeping patients most probably prone to encounter recurrence safe from possible side effects of BCG therapy. The assessment of NLRP4 expression and IL-1β levels could help predict failure of BCG therapy, playing an appreciable role in early deciding radical surgery. When comparing NLRP4 expression and IL-1β levels between MIBC and NMIBC cases, increased values were noted among non-invasive ones. This finding may serve as a possible diagnostic tool, which represents a challenging issue. Hence, cut-off values for gene expression and cytokine level are to be specified

    Reliability of using nondestructive tests to estimate compressive strength of building stones and bricks

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    This study aims to investigate the relationships between Schmidt hardness rebound number (RN) and ultrasonic pulse velocity (UPV) versus compressive strength (fc) of stones and bricks. Four types of rocks (marble, pink lime stone, white lime stone and basalt) and two types of burned bricks and lime-sand bricks were studied. Linear and non-linear models were proposed. High correlations were found between RN and UPV versus compressive strength. Validation of proposed models was assessed using other specimens for each material. Linear models for each material showed good correlations than non-linear models. General model between RN and compressive strength of tested stones and bricks showed a high correlation with regression coefficient R2 value of 0.94. Estimation of compressive strength for the studied stones and bricks using their rebound number and ultrasonic pulse velocity in a combined method was generally more reliable than using rebound number or ultrasonic pulse velocity only

    Long term study of mechanical

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    In this study, properties of limestone cement concrete containing different replacement levels of limestone powder were examined. It includes 0%, 5%, 10%, 15%, 20% and 25% of limestone powder as a partial replacement of cement. Silica fume was added incorporated with limestone powder in some mixes to enhance the concrete properties. Compressive strength, splitting tensile strength and modulus of elasticity were determined. Also, durability of limestone cement concrete with different C3A contents was examined. The weight loss, length change and cube compressive strength loss were measured for concrete attacked by 5% sodium sulfate using an accelerated test up to 525 days age. The corrosion resistance was measured through accelerated corrosion test using first crack time, cracking width and steel reinforcement weight loss. Consequently, for short and long term, the use of limestone up to 10% had not a significant reduction in concrete properties. It is not recommended to use blended limestone cement in case of sulfate attack. The use of limestone cement containing up to 25% limestone has insignificant effect on corrosion resistance before cracking

    Effect of filler types on physical, mechanical and microstructure of self compacting concrete and Flow-able concrete

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    The objective of this study is to evaluate the effect of various filler types on the fresh and hardened properties of self-compacting concrete (SCC) and Flow-able concrete. For this purpose, two groups of fillers were selected. The first group was pozzolanic fillers (silica fume and metakaolin) while the second group was non-pozzolanic fillers (limestone powder, granite dust and marble dust). Cement contents of 400 kg/m3 and 500 kg/m3 were considered while the used filler material was 7.5%, 10% and 15%. Slump and slump flow, T50, sieve stability and bleeding tests were performed on fresh concrete. The studied hardened properties included unit weight, voids ratio, porosity, and water absorption and cube compressive strength. In addition, thermo-gravimetric analysis, X-ray diffraction analysis and scanning electronic microscope were performed. The test results showed that filler type and content have significant effect on fresh concrete properties where non-pozzolanic fillers improve segregation and bleeding resistance. Generally, filler type and content have significant effect on unit weight, water absorption and voids ratio. In addition, non-pozzolanic fillers have insignificant negative effect on concrete compressive strength. Finally, there was a good correlation between fresh concrete properties and hardened concrete properties for SCC and Flow-able concrete

    Utilization of crushed clay brick in cellular concrete production

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    The main objective of this research program is to study the effect of using crushed clay brick as an alternative aggregate in aerated concrete. Two series of mixtures were designed to investigate the physico-mechanical properties and micro-structural analysis of autoclave aerated concrete and foamed concrete, respectively. In each series, natural sand was replaced with crushed clay brick aggregate. In both series results showed a significant reduction in unit weight, thermal conductivity and sound attenuation coefficient while porosity has increased. Improvement on compressive strength of autoclave aerated concrete was observed at a percentage of 25% and 50% replacement, while in foamed concrete compressive strength gradually decreased by increasing crushed clay brick aggregate content. A comparatively uniform distribution of pore in case of foamed concrete with natural sand was observed by scanning electron microscope, while the pores were connected mostly and irregularly for mixes containing a percentage higher than 25% clay brick aggregate

    Effect of Fiber Type and Volume Fraction on Fiber Reinforced Concrete and Engineered Cementitious Composite Mechanical Properties

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    Engineered cementitious composites (ECC) are an ultra-ductile cement-based composite material reinforced with short randomly distributed fibers. It differs from fiber reinforced concrete (FRC) in that it has a distinct ductile behavior. The study aims to assign mechanical properties, such as tensile, flexural, and compressive strength using locally available fiber rather than polyvinyl alcohol (PVA) fiber, which is not widely available in many countries, to ECC. PVA fiber is also very expensive. Instead of PVA, lightweight fibers, such as polypropylene, polyolefin, and glass fiber, as well as heavyweight fibers, such as steel fiber, were used. To assess the mechanical properties, the influences of curing, fiber volume fraction (2%, 4%, and 6%), fiber type, and fiber hybridization were adjusted in this study. The formation of multiple cracks along the specimen is the governing factor in ECC formation. The test results show that increasing the fiber volume fraction improves flexural and tensile strength. Water curing increased compressive, tensile, and flexural strength. Lightweight fiber hybridization has no effect on compressive strength, whereas heavyweight fiber hybridization improves compressive strength. For tensile and flexural strength, hybridization was associated with an improvement in all mechanical properties. The hybridization of lightweight fiber achieved ECC behavior at a lower volume fraction than the use of a single fiber volume. Relationships between tensile strength and flexural strength depending on the compressive strength of ECC were driven by demonstrating high performance

    Utilization of crushed clay brick in concrete industry

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    AbstractA comprehensive experimental program regarding the use of recycled aggregates produced from demolition of brick buildings is presented. The brick wastes were crushed, sorted and classified into coarse and fine aggregates as well as powder (CBP). The first phase of the research focuses on the effect of incorporating recycled aggregates on physico-mechanical properties of paste, mortar and concrete. Non-traditional tests including X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and micro-structural analysis (MSA) were performed. The second phase of the program explores the effect of using recycled aggregates on properties of concrete masonry units. A total of 44 mixtures were utilized throughout the program. Results show cement paste when modified with 25% CBP achieves smaller pore size and lower weight loss under high temperature than reference paste. Furthermore, the use of recycled aggregates reduces the overall unit weight of concrete masonry units. Actually, modified concrete masonry units incorporating recycled aggregates achieve lower unit weight, higher thermal resistance and absorption rate than reference units. Although considerable strength reduction is noticeable by substitution, compressive strength levels meet the Egyptian specifications limitations. Critical replacement ratios are suggested to produce load bearing-concrete masonry units. Based on experimental evidences, it can be stated that the use of recycled aggregate and dust made of clay bricks is promising in many applications where the thermal resistance, cost and environmental aspects are imperative

    Non-linear finite element modelling of dynamic loads on offshore structures

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    Bibliography: p. 243-252Structures utilized for the exploration and development of hydrocarbon resources in ice-covered water are by nature expensive and complex. Molikpaq, Gulfs Mobile Arctic Caisson, is one of such structures which was used successfully to drill in the Canadian Beaufort Sea. During one deployment of the caisson, it was subjected to ice interaction events resulting in critically large dynamic loads. Various models have recently been developed to describe the interaction between moving ice sheets and structures. While these models show considerable promise to adequately describe the problem, they do not provide a full description of the process nor have they yet met the challenge of modelling actual interactions. The main objective of this study is to develop a detailed non-linear finite element model which is capable of predicting the dynamic loading on offshore structures due to the movement of ice against them, and to study the behaviour of such structures under these dynamic effects. Molikpaq is taken as a study case in this work. The complete model consists of three major components: The structural model for the steel caisson and the sand core, the moving intact ice sheet, and the interaction between them. The structural model is developed using the sub-structuring technique to model the complicated steel caisson, while the sand core is modelled using simple three dimensional isoparametric elements. Continuum damage mechanics is employed to model the behaviour of the moving intact ice. A new finite element is developed to model the interface between the structure and the ice sheet. The element has two components: one to model the deformation and damage accumulation in the intact ice nearest to the structure, and one to model the extrusion of the pulverized ice between the intact ice and the structure. Details of the model components, and the parameters which affect them most, are explained in detail. The complete model is used to simulate some actual recorded events. It accurately predicts the loading and the structural response. The behaviour of the structural elements under these loadings is analyzed

    Prediction of concrete compressive strength due to long term sulfate attack using neural network

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    This work was divided into two phases. Phase one included the validation of neural network to predict mortar and concrete properties due to sulfate attack. These properties were expansion, weight loss, and compressive strength loss. Assessment of concrete compressive strength up to 200 years due to sulfate attack was considered in phase two. The neural network model showed high validity on predicting compressive strength, expansion and weight loss due to sulfate attack. Design charts were constructed to predict concrete compressive strength loss. The inputs of these charts were cement content, water cement ratio, C3A content, and sulfate concentration. These charts can be used easily to predict the compressive strength loss after any certain age and sulfate concentration for different concrete compositions
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